Purpose: Although prognostic factors of colorectal cancer have been studied, factors associated with liver metastasis have not been fully investigated. The aim of this study was to clarify the histopathologic characteristics of colorectal cancer with liver metastasis.
Methods: We performed a retrospective histopathologic study on 335 patients who underwent resection of colorectal cancer during 15 years. Histopathologic parameters of tumors with liver metastasis were compared with those without liver metastasis.
Results: Forty-one patients (12 percent) had simultaneous liver metastasis. Tumors having liver metastasis, when compared with those not having liver metastasis, were characterized by high frequency of tumor size more than 6 cm (51 vs. 28 percent; P < 0.01), presence of serosal invasion (98 vs. 66 percent; P < 0.01), lymphatic invasion (34 vs. 15 percent; P < 0.01), venous invasion (24 vs. 3 percent; P < 0.01), and lymph node metastasis (85 vs. 39 percent; P < 0.01). Multivariate analysis showed that factors independently associated with liver metastasis were serosal invasion, venous invasion, and lymph node metastasis. Accuracy in the diagnosis of liver metastasis was highest for venous invasion (88 percent) and lowest for serosal invasion (41 percent). Among 98 patients with both serosal invasion and lymph node metastasis, tumors with and without liver metastasis were different in frequency of venous invasion (26 vs. 6 percent; P < 0.01) and extracolic lymph node metastasis (68 vs. 47 percent; P < 0.05).
Conclusion: In colorectal cancer important factors associated with liver metastasis were serosal invasion, venous invasion, and lymph node metastasis. Significant determinants for liver metastasis from colorectal cancer were venous invasion and extracolic lymph node metastasis.